Toyota Lexusc Owner's Handbook Manual page 316

Using your audio system: some basics
This section describes some of the basic features of the Lexus
audio system. Some information may not pertain to your
system.
NOTICE
To prevent the battery from being discharged, do not
leave the car audio on longer than necessary when the
engine is not running.
Your audio system works when the ignition switch is in the
"ACC" or "ON" position.
AUDIO
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